1. Key Laboratory for Microstructural Material Physics of Hebei Province
2. School of Science
3. Yanshan University
4. Qinhuangdao 066004
5. P. R. China
6. CAS Key Laboratory of Magnetic Materials and Devices
7. Ningbo Institute of Materials Technology and Engineering
8. Chinese Academy of Sciences
9. Ningbo 315201
10. Ningbo University of Technology
11. Ningbo